1. Field of the Invention
This invention relates to the field of power supplies, and particularly to detecting errors in a stand-alone power supply using an internal test load.
2. Description of the Related Art
Even the most well-designed power supply is destined to fail, as is any system that it powers. They do not, however, necessarily fail at the same time. When one or the other fails, it can be challenging to tell where the real problem lies—in the system, or in the power supply. For example, many power supplies include two light-emitting diodes (“LEDs”)—an alternating current (“AC”) LED indicator and a direct current (“DC”) LED indicator. The AC LED is lit when the power supply is properly connected to an AC power source and is receiving expected power from it. The DC LED is lit when the power supply is operating normally and providing an expected power to the attached system.
When the DC LED is off, most customers generally assume that the problem is with the power supply; however, if the system overloads the power supply, short circuits, experiences fan blockage, or has code errors that direct the power supply off, the apparent problem with the power supply may actually be in the system. As a result, a customer might send the power supply back to the manufacturer for repair when, in fact, the power supply is operational and the system is experiencing errors.
These occurrences of “No Defect Found,” or NDF, present a serious problem. NDF rates can run as high 45% to 55% of all power supplies that are returned. Having such a high rate costs companies millions in services charges, time, shipping costs, and other associated expenses. In addition, it can be immensely frustrating to customers who receive a new or repaired power supply and insert it into the system, only to discover that the problems continue. It may take a number of return-and-replace cycles before the manufacturer or the customer realizes that the problem is not the power supply, but the system itself.
Existing solutions generally involve having the power supplies sent back to a service center where the power supple is extensively tested. As noted above, this imposes significant costs on the company and time costs on the consumer. Alternatively, companies have technicians go to the customer's site and diagnose the power supply using a sophisticated I2C communication error diagnostic tool. Again, this solution imposes a significant cost in terms of service times and expensive diagnostic tools. What is needed is an apparatus, system, and method that enables a customer or technician to quickly and effectively diagnose a power supply without incurring the substantial costs described above.